# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import copy
import unittest

import retworkx


class TestDeepcopy(unittest.TestCase):

    def test_deepcopy_returns_graph(self):
        dag_a = retworkx.PyGraph()
        node_a = dag_a.add_node('a_1')
        node_b = dag_a.add_node('a_2')
        dag_a.add_edge(node_a, node_b, 'edge_1')
        node_c = dag_a.add_node('a_3')
        dag_a.add_edge(node_b, node_c, 'edge_2')
        dag_b = copy.deepcopy(dag_a)
        self.assertIsInstance(dag_b, retworkx.PyGraph)

    def test_deepcopy_with_holes_returns_graph(self):
        dag_a = retworkx.PyGraph()
        node_a = dag_a.add_node('a_1')
        node_b = dag_a.add_node('a_2')
        dag_a.add_edge(node_a, node_b, 'edge_1')
        node_c = dag_a.add_node('a_3')
        dag_a.add_edge(node_b, node_c, 'edge_2')
        dag_a.remove_node(node_b)
        dag_b = copy.deepcopy(dag_a)
        self.assertIsInstance(dag_b, retworkx.PyGraph)
        self.assertEqual([node_a, node_c], dag_b.node_indexes())

    def test_deepcopy_empty(self):
        dag = retworkx.PyGraph()
        empty_copy = copy.deepcopy(dag)
        self.assertEqual(len(empty_copy), 0)